Dynamic Changes in PD-L1 Expression and Immune Infiltrates Early During Treatment Predict Response to PD-1 Blockade in Melanoma

Myeloid Cells as Clinical Biomarkers for Immune Checkpoint Blockade

Immune checkpoint inhibitors are becoming standard treatments in several cancer types, profoundly changing the prognosis of a fraction of patients. Currently, many efforts are being made to predict responders and to understand how to overcome resistance in non-responders. Given the crucial role of myeloid cells as modulators of T effector cell function in tumors, it is essential to understand their impact on the clinical outcome of immune checkpoint blockade and on the mechanisms of immune evasion. In this review we focus on the existing clinical evidence of the relation between the presence of myeloid cell subsets and the response to anti-PD(L)1 and anti-CTLA-4 treatment. We highlight how circulating and tumor-infiltrating myeloid populations can be used as predictive biomarkers for immune checkpoint inhibitors in different human cancers, both at baseline and on treatment. Moreover, we propose to follow the dynamics of myeloid cells during immunotherapy as pharmacodynamic biomarkers. Finally, we provide an overview of the current strategies tested in the clinic that use myeloid cell targeting together with immune checkpoint blockade with the aim of uncovering the most promising approaches for effective combinations.

A Prognostic Nomogram Based on Immune Scores Predicts Postoperative Survival for Patients with Hepatocellular Carcinoma

Background

Increasing research attention has focused on tumor-infiltrating immune cells. However, the threshold of an immune score for use in predicting overall survival (OS) and disease-free survival (DFS) in hepatocellular carcinoma (HCC) is not defined. This study aims at exploring the association between immune scores with prognosis and building a clinical nomogram for predicting the survival of HCC patients. Material and Methods. A total of 299 patients were enrolled in this study. Their clinical pathological characteristics and immune scores downloaded from The Cancer Genome Atlas (TCGA) database were analyzed. Survival differences between different immune score subgroups were compared, and a final nomogram was built using the Cox proportional hazards regression model. The predictive performance of the nomogram was assessed using the concordance index (C-index) and a calibration plot.

Results

All the patients were divided into three subgroups based on immune scores. Patients with medium and high immune scores had significantly better OS (HR and 95% CI: 0.417 [0.186-0.937] and 0.299 [0.146-0.616]) and DFS (HR and 95% CI: 0.575 [0.329-1.004] and 0.451 [0.278-0.733], respectively, compared with those with low immune scores. The C indices for OS and DFS were 0.748 (95% CI, 0.687-0.809) and 0.675 (95% CI, 0.630-0.720), respectively. A calibration plot used to determine the probability of survival at 3 or 5 years (OS and DFS) showed a significant agreement between nomogram predictions and actual observations.

Conclusions

Medium and high immune scores are significantly associated with prolonged OS and DFS in HCC patients. Nomograms built in this study can help doctors and patients assess prognosis and guide treatment.

Tumor-induced neurogenesis and immune evasion as targets of innovative anti-cancer therapies

Normal cells are hijacked by cancer cells forming together heterogeneous tumor masses immersed in aberrant communication circuits that facilitate tumor growth and dissemination. Besides the well characterized angiogenic effect of some tumor-derived factors; others, such as BDNF, recruit peripheral nerves and leukocytes. The neurogenic switch, activated by tumor-derived neurotrophins and extracellular vesicles, attracts adjacent peripheral fibers (autonomic/sensorial) and neural progenitor cells. Strikingly, tumor-associated nerve fibers can guide cancer cell dissemination. Moreover, IL-1β, CCL2, PGE₂, among other chemotactic factors, attract natural immunosuppressive cells, including T regulatory (Tregs), myeloid-derived suppressor cells (MDSCs), and M2 macrophages, to the tumor microenvironment. These leukocytes further exacerbate the aberrant communication circuit releasing factors with neurogenic effect. Furthermore, cancer cells directly evade immune surveillance and the antitumoral actions of natural killer cells by activating immunosuppressive mechanisms elicited by heterophilic complexes, joining cancer and immune cells, formed by PD-L1/PD1 and CD80/CTLA-4 plasma membrane proteins. Altogether, nervous and immune cells, together with fibroblasts, endothelial, and bone-marrow-derived cells, promote tumor growth and enhance the metastatic properties of cancer cells. Inspired by the demonstrated, but restricted, power of anti-angiogenic and immune cell-based therapies, preclinical studies are focusing on strategies aimed to inhibit tumor-induced neurogenesis. Here we discuss the potential of anti-neurogenesis and, considering the interplay between nervous and immune systems, we also focus on anti-immunosuppression-based therapies. Small molecules, antibodies and immune cells are being considered as therapeutic agents, aimed to prevent cancer cell communication with neurons and leukocytes, targeting chemotactic and neurotransmitter signaling pathways linked to perineural invasion and metastasis.

Immune Checkpoint Inhibitors in Hepatocellular Cancer: Current Understanding on Mechanisms of Resistance and Biomarkers of Response to Treatment

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy worldwide and a leading cause of death worldwide. Its incidence continues to increase in the US due to hepatitis C infection and nonalcoholic steatohepatitis. Liver transplantation and resection remain the best therapeutic options for cure, but these are limited by the shortage of available organs for transplantation, diagnosis at advanced stage, and underlying chronic liver disease found in most patients with HCC. Immune checkpoint inhibitors (ICIs) have been shown to be an evolving novel treatment option in certain advanced solid tumors and have been recently approved for inoperable, advanced, and metastatic HCC. Unfortunately, a large cohort of patients with HCC fail to respond to immunotherapy. In this review, we discuss the ICIs currently approved for HCC treatment and their various mechanisms of action. We will highlight current understanding of mechanism of resistance and limitations to ICIs. Finally, we will describe emerging biomarkers of response to ICIs and address future direction on overcoming resistance to immune checkpoint therapy.

Immune checkpoint blockade in solid organ tumours: Choice, dose and predictors of response

Immune checkpoint blockade has transformed outcomes across solid organ tumours. Monoclonal antibodies targeting the negative inhibitory cytotoxic T lymphocyte-associated protein 4 and programmed-death 1/programmed death-ligand 1 axis can lead to deep and durable responses across several tumour streams in the advanced setting. This immunotherapy approach is increasingly used earlier in the treatment paradigm. A rapidly evolving regulatory, reimbursement and drug development landscape has accompanied this novel class of immunotherapy. Unfortunately, only a small proportion of patients respond meaningfully to these agents. Here we review how the underlying tumoural genomic, histological and immunological characteristics interact within various patient phenotypes, leading to variations in response to checkpoint blockade. Concurrently, we outline the clinical trial and real-world evidence that allows for appropriate selection of agent, dose and schedule in solid organ malignancies. An exploration of current trends in basic and translational research in immune checkpoint blockade accompanies a commentary on future clinical directions for checkpoint blockade in oncology.

Anti-PD-1 Therapy Response Predicted by the Combination of Exosomal PD-L1 and CD28

Anti-PD-1 therapy has been approved for cancer treatment. However, the response rate is unsatisfactory. The expression of PD-L1 in tumor tissues is unreliable to predict the treatment response. Recent studies have suggested that exosomal PD-L1 not only exerts immunosuppressive effects but also plays a significant role in the development of tumor microenvironment. Thus, the present study aims to investigate exosomal PD-L1 in improving its predictive value and efficacy. A total of 44 patients of advanced tumors of several types, treated with anti-PD-1 therapy, were enrolled. Exosomes were collected and purified from plasma. The exosomal PD-L1 was detected with ELISA. The cytokines were measured with the MILLIPLEX magnetic bead assay. Compared to the responders, exosomal PD-L1 of the non-responders was significantly higher than that of the responders (P = 0.010) before the treatment. Concurrently, exosomal PD-L1 and tumor burden decreased when the therapy was effective. And, the baseline expression of CD28 was higher in the responders than that in the non-responders (P = 0.005). Univariate and multivariate analyses validated with 1,000 times bootstrapping suggested that high exosomal PD-L1 and low CD28 expressions were negative factors for progression-free survival (PFS) of the patients who underwent anti-PD-1 treatment. The combination of exosomal PD-L1 and CD28 obtained more area under the curve (AUC) of receiver operating characteristic (ROC) (AUC 0.850 vs. 0.784 vs. 0.678) and showed a higher probability of no progression via nomograph. These findings suggested that the expression of exosomal PD-L1 and CD28 could serve as the predictive biomarkers for clinical responses to anti-PD-1 treatment.

PD-L1 expression correlates with tumor-infiltrating lymphocytes and better prognosis in patients with HPV-negative head and neck squamous cell carcinomas

INTRODUCTION

The importance of immune tumor microenvironment in the prognosis of patients with head and neck squamous carcinomas (HNSCC) is increasingly recognized. We analyzed the prognostic relevance of PD-L1 and PD-1 expressions in relation to the infiltration by CD8⁺ and FOXP3⁺ tumor-infiltrating lymphocytes (TILs).

METHODS

Samples from 372 surgically treated HPV-negative HNSCC patients were evaluated by immunohistochemistry for PD-L1 expression [both tumor proportion score (TPS) and combined proportion score (CPS)], PD-1 expression in immune cells, and density of infiltrating CD8⁺ and FOXP3⁺ TILs. PD-L1 expression and CD8⁺ TIL density were combined to establish the type of tumor microenvironment.

RESULTS

29.5% cases exhibited PD-L1 TPS positivity (≥ 1%), whereas PD-L1 CPS positivity (≥ 1%) was observed in 40% cases. 47.5% cases showed positive PD-1 expression (≥ 1%). PD-L1 and PD-1 positivity correlated with a high density of both CD8⁺ and FOXP3⁺ TILs. In univariate analysis, PD-L1 TPS positivity (P = 0.026), PD-L1 CPS positivity (P = 0.004), high density of CD8⁺ TIL (P = 0.001), and high density of FOXP3⁺ TIL (P = 0.004) were associated with a better disease-specific survival (DSS). However, in multivariate analysis, only high density of CD8⁺ TIL was associated with a better DSS (P = 0.002). The type of tumor microenvironment correlated with DSS (P = .008), with the better DSS observed in cases with type I (PD-L1 CPS positivity and high density of CD8⁺ TIL).

CONCLUSIONS

High infiltration by CD8⁺ TIL is associated with better survival outcomes. Positive PD-L1 expression correlates with a high infiltration by TILs, explaining its association with better prognosis.

Differences of the Immune Phenotype of Breast Cancer Cells after Ex Vivo Hyperthermia by Warm-Water or Microwave Radiation in a Closed-Loop System Alone or in Combination with Radiotherapy

The treatment of breast cancer by radiotherapy can be complemented by hyperthermia. Little is known about how the immune phenotype of tumor cells is changed thereby, also in terms of a dependence on the heating method. We developed a sterile closed-loop system, using either a warm-water bath or a microwave at 2.45 GHz to examine the impact of ex vivo hyperthermia on cell death, the release of HSP70, and the expression of immune checkpoint molecules (ICMs) on MCF-7 and MDA-MB-231 breast cancer cells by multicolor flow cytometry and ELISA. Heating was performed between 39 and 44 °C. Numerical process simulations identified temperature distributions. Additionally, irradiation with 2 × 5 Gy or 5 × 2 Gy was applied. We observed a release of HSP70 after hyperthermia at all examined temperatures and independently of the heating method, but microwave heating was more effective in cell killing, and microwave heating with and without radiotherapy increased subsequent HSP70 concentrations. Adding hyperthermia to radiotherapy, dynamically or individually, affected the expression of the ICM PD-L1, PD-L2, HVEM, ICOS-L, CD137-L, OX40-L, CD27-L, and EGFR on breast cancer cells. Well-characterized pre-clinical heating systems are mandatory to screen the immune phenotype of tumor cells in clinically relevant settings to define immune matrices for therapy adaption.

Effects of anti-PD-1 immunotherapy on tumor regression: insights from a patient-derived xenograft model

Immunotherapies, such as checkpoint blockade of programmed cell death protein-1 (PD-1), have resulted in unprecedented improvements in survival for patients with lung cancer. Nonetheless, not all patients benefit equally and many issues remain unresolved, including the mechanisms of action and the possible effector function of immune cells from non-lymphoid lineages. The purpose of this study was to investigate whether anti-PD-1 immunotherapy acts on malignant tumor cells through mechanisms beyond those related to T lymphocyte involvement. We used a murine patient-derived xenograft (PDX) model of early-stage non–small cell lung carcinoma (NSCLC) devoid of host lymphoid cells, and studied the tumor and immune non-lymphoid responses to immunotherapy with anti-PD-1 alone or in combination with standard chemotherapy (cisplatin). An antitumor effect was observed in animals that received anti-PD-1 treatment, alone or in combination with cisplatin, likely due to a mechanism independent of T lymphocytes. Indeed, anti-PD-1 treatment induced myeloid cell mobilization to the tumor concomitant with the production of exudates compatible with an acute inflammatory reaction mediated by murine polymorphonuclear leukocytes, specifically neutrophils. Thus, while keeping in mind that more research is needed to corroborate our findings, we report preliminary evidence for a previously undescribed immunotherapy mechanism in this model, suggesting a potential cytotoxic action of neutrophils as PD-1 inhibitor effector cells responsible for tumor regression by necrotic extension.

Identification of Potential Biomarkers for Anti-PD-1 Therapy in Melanoma by Weighted Correlation Network Analysis

Melanoma is the most malignant form of skin cancer, which seriously threatens human life and health. Anti-PD-1 immunotherapy has shown clinical benefits in improving patients' overall survival, but some melanoma patients failed to respond. Effective therapeutic biomarkers are vital to evaluate and optimize benefits from anti-PD-1 treatment. Although the establishment of immunotherapy biomarkers is well underway, studies that identify predictors by gene network-based approaches are lacking. Here, we retrieved the existing datasets (GSE91061, GSE78220 and GSE93157, 79 samples in total) on anti-PD-1 therapy to explore potential therapeutic biomarkers in melanoma using weighted correlation network analysis (WGCNA), function validation and clinical corroboration. As a result, 13 hub genes as critical nodes were traced from the key module associated with clinical features. After receiver operating characteristic (ROC) curve validation by an independent dataset (GSE78220), six hub genes with diagnostic significance were further recovered. Moreover, these six genes were revealed to be closely associated not only with the immune system regulation, immune infiltration, and validated immunotherapy biomarkers, but also with excellent prognostic value and significant expression level in melanoma. The random forest prediction model constructed using these six genes presented a great diagnostic ability for anti-PD-1 immunotherapy response. Taken together, IRF1, JAK2, CD8A, IRF8, STAT5B, and SELL may serve as predictive therapeutic biomarkers for melanoma and could facilitate future anti-PD-1 therapy.

Mass Spectrometry Imaging Reveals Neutrophil Defensins as Additional Biomarkers for Anti-PD-(L)1 Immunotherapy Response in NSCLC Patients

(1) Background: Therapeutic blocking of the interaction between programmed death-1 (PD-1) with its ligand PD-L1, an immune checkpoint, is a promising approach to restore the antitumor immune response. Improved clinical outcomes have been shown in different human cancers, including non-small cell lung cancer (NSCLC). Unfortunately, still a high number of NSCLC patients are treated with immunotherapy without obtaining any clinical benefit, due to the limitations of PD-L1 protein expression as the currently sole predictive biomarker for clinical use; (2) Methods: In this study, we applied mass spectrometry imaging (MSI) to discover new protein biomarkers, and to assess the possible correlation between candidate biomarkers and a positive immunotherapy response by matrix-assisted laser desorption/ionization (MALDI) MSI in 25 formalin-fixed paraffin-embedded (FFPE) pretreatment tumor biopsies (Biobank@UZA); (3) Results: Using MALDI MSI, we revealed that the addition of neutrophil defensin 1, 2 and 3 as pretreatment biomarkers may more accurately predict the outcome of immunotherapy treatment in NSCLC. These results were verified and confirmed with immunohistochemical analyses. In addition, we provide in-vitro evidence of the immune stimulatory effect of neutrophil defensins towards cancer cells; and (4) Conclusions: With proteomic approaches, we have discovered neutrophil defensins as additional prospective biomarkers for an anti-PD-(L)1 immunotherapy response. Thereby, we also demonstrated that the neutrophil defensins contribute in the activation of the immune response towards cancer cells, which could provide a new lead towards an anticancer therapy.

Dynamic monitoring of serum soluble programmed cell death ligand 1 as a response predictor to chemotherapy in metastatic or recurrent gastrointestinal cancer

Background

Biomarkers in serum may have important clinical implications for personalized medicine, including therapeutic guidance, and monitoring of recurrence. The role of programmed cell death ligand 1 (PD-L1) expression as a tumor biomarker remains controversial. In this study, we aimed at determining the changes of soluble PD-L1 (sPD-L1) during first-line chemotherapy and assessing the association with treatment response and progression-free survival (PFS) of patients with advanced gastrointestinal cancer.

Methods

Blood samples from 115 gastrointestinal cancer patients who have not received any previous systemic chemotherapy for recurrent or metastatic disease were collected at the time of diagnosis and each response evaluation. Serum of sPD-L1 expression was tested by enzyme-linked immunosorbent assay (ELISA). The associations between the baseline level of serum sPD-L1 and clinical-pathological characteristics and prognosis were analyzed. we further dynamically monitored the level change of serum sPD-L1 during treatment and analyzed its relationship with clinical-pathological characteristics, chemotherapy response and prognosis.

Results

Among 115 metastatic gastrointestinal patients, the median serum sPD-L1 level was 0.777 (range, <0.156–6.680) ng/mL. In most cases, changes in sPD-L1 level correlated with treatment response. Patients with values of serum sPD-L1 decreasing after chemotherapy had better tumor response and median PFS compared with patients with values increasing after chemotherapy (ORR, 88.3% vs. 54.0% P=0.000005 and PFS, not reached vs. 27 months, P=0.00026). D-values of sPD-L1 in patients with progressive disease (PD) were observed increasing from 0.406 to 1.097 ng/mL between pre- and post-chemotherapy, while in those with better tumor response D-values decreased from 1.153 to 0.791 ng/mL after chemotherapy compared with baseline. In the logistic regression analysis, the change of sPD-L1 levels in serum after chemotherapy were found to be a prognostic factor for treatment response and PFS in the multivariate analysis.

Conclusions

These results showed for the first time that sPD-L1 in serum samples of patients with advanced gastrointestinal cancer were changed after chemotherapy and increased serum sPD-L1 levels were poor prognostic factors for both tumor response and PFS of patients. Dynamic monitoring of serum sPDL1 after treatment may be served as a potential predictor to treatment response in gastrointestinal cancer patients.

Modern Aspects of Immunotherapy with Checkpoint Inhibitors in Melanoma

Although melanoma is one of the most immunogenic tumors, it has an ability to evade anti-tumor immune responses by exploiting tolerance mechanisms, including negative immune checkpoint molecules. The most extensively studied checkpoints represent cytotoxic T lymphocyte-associated protein-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Immune checkpoint inhibitors (ICI), which were broadly applied for melanoma treatment in the past decade, can unleash anti-tumor immune responses and result in melanoma regression. Patients responding to the ICI treatment showed long-lasting remission or disease control status. However, a large group of patients failed to respond to this therapy, indicating the development of resistance mechanisms. Among them are intrinsic tumor properties, the dysfunction of effector cells, and the generation of immunosuppressive tumor microenvironment (TME). This review discusses achievements of ICI treatment in melanoma, reasons for its failure, and promising approaches for overcoming the resistance. These methods include combinations of different ICI with each other, strategies for neutralizing the immunosuppressive TME and combining ICI with other anti-cancer therapies such as radiation, oncolytic viral, or targeted therapy. New therapeutic approaches targeting other immune checkpoint molecules are also discussed.

Immunotherapy for skin cancer

Among all tumor types, skin cancers are profoundly sensitive to immunotherapy. Indeed, the recently reported response rates for anti-PD-1 (anti-programmed-death 1) therapy for cutaneous malignant melanomas (MM), Merkel cell carcinomas, basal cell carcinomas, cutaneous squamous cell carcinomas and Kaposi sarcomas are all above 40%. This unique immunogenicity renders skin cancers as a paradigm for tumor-immune interactions and is driven by high mutational burdens, over-expressed tumor antigens and/or viral antigens. However, despite the clear demonstration of immunologic cure of skin cancer in some patients, most tumors develop either early (primary) or late (adaptive) resistance to immunotherapy. Resistance mechanisms are complex, and include contributions of tumor cell-intrinsic, T cell and microenvironment factors that have been recently further elucidated with the advent of single-cell technologies. This review will focus on the exciting progress with immunotherapy for skin cancers to date, and also our current understanding of the mechanisms of resistance to immunotherapy.

Advances in theranostic biomarkers for tumor immunotherapy

Cancer treatment has known a revolution with the emergence of immune checkpoint inhibitors. However, accurate theranostic biomarkers are lacking. In this review, we discuss different types of biomarkers currently under investigation. First, we focus on tissue biomarkers including PD-L1 expression by immunohistochemistry-the first Food and Drug Administration-approved biomarker-despite conflicting results. In addition, we report on novel biomarkers, including protein-based, molecular (tumor mutational load, immune signature…), circulating (neutrophil-to-lymphocyte ratio, serum cytokines…), and imaging-based biomarkers (radiomic signatures and positron-emission tomography using radiolabeled antibodies). We highlight the limitations of each candidate biomarker and finally discuss combinatorial approaches for their use and the opportunity to switch from a predictive strategy of biomarker research to an adaptive one in the field of cancer immunotherapy.

Combining Immune Checkpoint Inhibitors with Anti-Angiogenic Agents

Immunotherapy has recently emerged as a novel strategy for treating different types of solid tumors, with promising results. However, still a large fraction of patients do not primarily respond to such approaches, and even responders sooner or later develop resistance. Moreover, immunotherapy is a promising strategy for certain malignancies but not for others, with this discrepancy having been attributed to a more immunogenic microenvironment of some tumors. As abnormal and augmented tumor vessels often occur in cancerogenesis, anti-angiogenic drugs have already demonstrated their effectiveness both in preclinical and in clinical settings. By targeting abnormal formation of tumor vessels, anti-angiogenetic agents potentially result in an enhanced infiltration of immune effector cells. Moreover, crosstalks downstream of the immune checkpoint axis and vascular endothelial growth factor receptor (VEGFR) signaling may result in synergistic effects of combined treatment in tumor cells. In this review, we will describe and discuss the biological rationale of a combined therapy, underlying the modification in tumor microenvironment as well as in tumor cells after exposure to checkpoint inhibitors and anti-angiogenic drugs. Moreover, we will highlight this strategy as a possible way for overcoming drug resistance. By first discussing potential prognostic and predictive factors for combined treatment, we will then turn to clinical settings, focusing on clinical trials where this strategy is currently being investigated.

PD-L1 Detection-Pearls and Pitfalls Associated With Current Methodologies Focusing on Entities Relevant to Dermatopathology

PD-L1 is a transmembrane glycoprotein with an extracellular as well as an intracellular cytoplasmic domain. Physiologically, it plays a pivotal role in regulating T-cell activation and tolerance. Many tumor cells have exploited this regulatory mechanism by overexpressing PD-L1 in an effort to escape immunologic surveillance. In this review, we parse the literature regarding the prognostic value of tumoral PD-L1 expression before discussing the various methodologies as well as the pearls and pitfalls associated with each for predicting response to anti-PD-1/PD-L1 therapies. Special attention is given to cutaneous entities in which PD-L1 expression has been documented with an emphasis on cutaneous malignancies that have seen the broadest applications of anti-PD-L1/PD-1 therapies. Currently, immunohistochemistry is the method that is most commonly used for detection of PD-L1. However, with the wide array of immunohistochemistry protocols and staining platforms available in the market, there seems to be different cutoffs not just for different entities but also for the same entity. This review is an attempt to address the need for standardization and validation of existing protocols for PD-L1 detection.

Possibilities of Improving the Clinical Value of Immune Checkpoint Inhibitor Therapies in Cancer Care by Optimizing Patient Selection

Immune checkpoint inhibitor (ICI) therapies have become the most important medical therapies in many malignancies, such as melanoma, non-small-cell lung cancer, and urogenital cancers. However, due to generally low response rates of PD-(L)1 monotherapy, both PD-(L)1 combination therapies and novel therapeutics are under large-scale clinical evaluation. Thus far, clinical trials have rather suboptimally defined the patient population most likely to benefit from ICI therapy, and there is an unmet need for negative predictive markers aiming to reduce the number of non-responding patients in clinical practice. Furthermore, there is a strong need for basic tumor immunology research and innovative clinical trials to fully unleash the potential of ICI combinations for the benefit of patients.

Spatiotemporal Changes in Checkpoint Molecule Expression

Immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 blockade, have led to therapeutic breakthrough in patients with advanced malignancy, covering the lung, breast, gastrointestinal, head and neck, urinary system, lymphoma, and solid tumor harboring MSI/dMMR. In certain cancer types, the expression level of immune checkpoint molecule will be required if the immune-based approaches are considered, especially the PD-L1 expression. However, in other types, survival benefit has been proven regardless of PD-L1 expression. It raises a question of how to select patients for immune therapy and whether the expression of immune checkpoint molecules will be optimal biomarkers. Before answering this question, a comprehensive map for the expression of immune checkpoint molecules is needed. In this chapter, we describe our current knowledge on the spatiotemporal changes in the expression of checkpoint molecules. We discuss the different frequencies of expression depending on tumor types and stages, the different patterns between primary and metastatic tumors, as well as the change of expression before and after treatment. The expression of PD-L1 has been most studied, but the threshold that separate "positive" and "negative" PD-L1 expressions and the consistency of testing platform remain under debate. Better understanding on the tumor microenvironment and expression of checkpoint molecules will help to identify patients who will benefit from checkpoint blockade therapy.

Molecular imaging biomarkers for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have substantially changed the field of oncology over the past few years. ICIs offer an alternative treatment strategy by exploiting the patients' immune system, resulting in a T cell mediated anti-tumor response. These therapies are effective in multiple different tumor types. Unfortunately, a substantial group of patients do not respond to ICIs. Molecular imaging, using single-photon emission computed tomography (SPECT) and positron emission tomography (PET), can provide non-invasive whole-body visualization of tumor and immune cell characteristics and might support patient selection or response evaluations for ICI therapies. In this review, recent studies with 18F-fluorodeoxyglucose-PET imaging, imaging of immune checkpoints and imaging of immune cells will be discussed. These studies are until now mainly exploratory, but the first results suggest that molecular imaging biomarkers could have a role in the evaluation of ICI therapy.

Single-Molecule Arrays for Ultrasensitive Detection of Blood-Based Biomarkers for Immunotherapy

Single-molecule array (Simoa) technology enables ultrasensitive protein detection that is suited to the development of peripheral blood-based assays for assessing immuno-oncology responses. We adapted a panel of Simoa assays to measure systemic cytokine levels from plasma and characterized physiologic variation in healthy individuals and preanalytic variation arising from processing and handling of patient samples. Insights from these preclinical studies led us to a well-defined set of Simoa assay conditions, a specimen processing protocol, and a data processing approach that we describe here. Simoa enables accurate quantitation of soluble immune signaling molecules in an unprecedented femtomolar range, opening up the potential for liquid biopsy-type approaches in immuno-oncology. We are using the method described here to distinguish PD-1 inhibitor nonresponders as early as after one dose after therapy and envision applications in characterizing PD-1 inhibitor resistance and detection of immune-related adverse effects.

Case Report: A Case of Pituitary Carcinoma Treated With Sequential Dual Immunotherapy and Vascular Endothelial Growth Factor Inhibition Therapy

Aggressive pituitary tumors (APTs) are associated with significant morbidity and mortality, and effective treatment options are limited. Immune checkpoint inhibitors (ICIs) have revolutionized clinical cancer care; however, there is little experience with these agents in the management of APTs. Vascular endothelial growth factor (VEGF) targeted therapy has reported success in a small number of APT case reports. Here we describe a case of pituitary carcinoma responding to ICI therapy and subsequently VEGF inhibition. We discuss the possible mechanisms and experience with ICI therapy and VEGF inhibitors in the management of APTs, biomarkers that may predict response, and the potential role of combination therapies including ICIs and temozolomide.

Tumor microenvironmental influences on dendritic cell and T cell function: A focus on clinically relevant immunologic and metabolic checkpoints

Cancer immunotherapy is fast becoming one of the most promising means of treating malignant disease. Cancer vaccines, adoptive cell transfer therapies, and immune checkpoint blockade have all shown varying levels of success in the clinical management of several cancer types in recent years. However, despite the clinical benefits often achieved by these regimens, an ongoing problem for many patients is the inherent or acquired resistance of their cancer to immunotherapy. It is now appreciated that dendritic cells and T lymphocytes both play key roles in antitumor immune responses and that the tumor microenvironment presents a number of barriers to the function of these cells that can ultimately limit the success of immunotherapy. In particular, the engagement of several immunologic and metabolic checkpoints within the hostile tumor microenvironment can severely compromise the antitumor functions of these important immune populations. This review highlights work from both preclinical and clinical studies that has shaped our understanding of the tumor microenvironment and its influence on dendritic cell and T cell function. It focuses on clinically relevant targeted and immunotherapeutic strategies that have emerged from these studies in an effort to prevent or overcome immune subversion within the tumor microenvironment. Emphasis is also placed on the potential of next-generation combinatorial regimens that target metabolic and immunologic impediments to dendritic cell and T lymphocyte function as strategies to improve antitumor immune reactivity and the clinical outcome of cancer immunotherapy going forward.

Tumor intrinsic and extrinsic immune functions of CD155

CD155 (PVR/necl5/Tage4), a member of the nectin-like family of adhesion molecules, is highly upregulated on tumor cells across multiple cancer types and has been associated with worse patient outcomes. In addition to well described cell-intrinsic roles promoting tumor progression and metastasis, CD155 has now been implicated in immune regulation. The role of CD155 as a potent immune ligand with diverse cell-extrinsic functions is now being defined. CD155 signaling to immune cells is mediated through interactions with the co-stimulatory immune receptor CD226 (DNAM-1) and the inhibitory checkpoint receptors TIGIT and CD96, which are differentially regulated at the cell surface on T cells and NK cells. The integration of signals from CD155 cognate receptors modifies the activity of tumor-infiltrating lymphocytes in a context-dependent manner, making CD155 an attractive target for immune-oncology. Preclinical studies suggest that targeting this axis can improve immune-mediated tumor control, particularly when combined with existing anti-PD-1 checkpoint therapies. In this review, we discuss the roles of CD155 on host and tumor cells in controlling tumor progression and discuss the possibility of targeting CD155 for cancer therapy.

FDG-PET response and outcome from anti-PD-1 therapy in metastatic melanoma

Background

Immune checkpoint inhibitor therapy has resulted in impressive and durable clinical activity for many cancers including melanoma; however, there remain few reliable predictors for long-term response. This study investigated whether [18F]2-fluoro-2-deoxy-D-glucose (FDG-PET) imaging may better predict long-term outcomes compared with standard computed tomography (CT) response criteria.

Patients and methods

Retrospective analysis of metastatic melanoma patients treated with anti-PD-1-based immunotherapy with baseline and 1-year FDG-PET and CT imaging at Melanoma Institute Australia. One-year response was determined using RECIST for CT and EORTC criteria for PET, coded as complete response (CR or CMR), partial response (PR or PMR), stable disease (SD or SMD) or progressive disease (PD or PMD). Progression-free survival (PFS) was determined from the 1-year landmark.

Results

Patients (n = 104) were evaluated with median follow-up 30.1 months and 98% remain alive. Most received anti-PD-1 as monotherapy (67%) or combined with ipilimumab (31%). At 1 year, 28% had CR, 66% had PR and 6% had SD on CT, while 75% had CMR, 16% PMR and 9% SMD/PMD on PET. CMR was observed in 68% of patients with PR on CT. RECIST PFS post 1-year landmark was similar in patients with CR versus PR/SD, but improved in patients with CMR versus non-CMR {median not reached [NR] versus 12.8 month; hazard ratio [HR] 0.06 [95% confidence interval (CI) 0.02-0.23]; P < 0.01}. In patients with PR on CT, PFS was improved in patients with PR + CMR versus PR + non-CMR (median NR versus 12.8 months; HR 0.07 [95% CI 0.02-0.27]; P < 0.01). In the 78 CMR patients, 78% had discontinued treatment and 96% had ongoing response.

Conclusions

Whilst only a small proportion of patients have a CR at 1 year, most patients with a PR have CMR on PET. Almost all patients with CMR at 1 year have ongoing response to therapy thereafter. PET may have utility in predicting long-term benefit and help guide discontinuation of therapy.

Alterations in composition of immune cells and impairment of anti-tumor immune response in aged oral cancer-bearing mice

OBJECTIVES

Aging has been suggested to be associated with immune dysregulation. An understanding of alterations in the host immunity with advancing age is, therefore, important for designing immune therapy for elderly cancer patients. In this context, not much is known about age-associated alterations in the immune system in oral cancer.

METHODS

To evaluate age-associated alterations in the immune system, which might affect anti-tumor immune responses in oral cancer, we performed a comparative analysis of the proportion of different immune cells, the proliferative capacity of T cell compartment, and the response against immune therapies targeting immune check point molecules between young and aged oral cancer-bearing mice.

RESULTS

The proportion of immune regulatory cells, such as regulatory T cells and myeloid derived suppressor cells, was significantly increased in aged mice compared to that in young mice. Moreover, the expression of PD-1 and CTLA-4 on both CD4⁺ and CD8⁺ T cells was elevated in aged mice compared to that in young mice, and the proliferative abilities of CD4⁺ and CD8⁺ T cells derived from aged mice were significantly reduced following stimulation of T-cell receptors. Moreover, tumor growth was significantly enhanced in aged mice compared to that in young mice. However, immunotherapies targeting PD-1, CTLA-4, and PD-L1 resulted in faster tumor regression in aged mice than in young mice.

CONCLUSIONS

Together, our results indicate that age-associated alterations in the immune system are directly associated with the impairment of anti-tumor immunity in aged mice bearing oral cancer, and might facilitate the progression of the tumor.

Close proximity of immune and tumor cells underlies response to anti-PD-1 based therapies in metastatic melanoma patients

Immune checkpoint blockade has greatly improved the clinical outcomes of many patients with metastatic melanoma, however, almost half do not respond. Whether the interspatial distribution of immune and tumor cells predicts response to anti-PD-1-based therapies and patient outcomes in any cancer, including melanoma, is currently unknown. Here, we examined the spatial distribution of immune and tumor cells via multiplex immunofluorescence. Pre-treatment melanoma specimens from 27 patients (n = 18 responders; n = 9 non-responders) treated with anti-PD-1 monotherapy and 34 patients (n = 22 responders; n = 12 non-responders) treated with combined ipilimumab and anti-PD-1 immunotherapy were studied. Responders displayed significantly higher densities of CD8⁺ tumor-infiltrating lymphocytes within a 20 µM distance from a melanoma cell compared to non-responders in both anti-PD-1 alone (p = .0024) and combination-treated patients (p = .0096), that were associated with improved progression-free survival for both therapies (anti-PD-1 p = .0158; combination therapy p = .0088). In multivariate analysis, the best model for 12-month progression-free survival for anti-PD-1 monotherapy included PD-L1⁺ cells within proximity to tumor cells and intratumoral CD8⁺ density (AUC = 0.80), and for combination therapy included CD8⁺ cells in proximity to tumor cells, intratumoral PD-L1⁺ density and LDH (AUC = 0.85). Assessment of the spatial distribution of immune cells in relation to tumor cells provides insight into their role in modulating immune response and highlights their potential role as predictors of response to anti-PD-1 based therapies.

A Long-term Response to Nivolumab in a Case of PD-L1-negative Lung Adenocarcinoma with an EGFR Mutation and Surrounding PD-L1-positive Tumor-associated Macrophages

Anti-programmed cell death 1 (PD-1) antibodies have poor efficacy in epidermal growth factor receptor (EGFR)-mutated lung cancer. We herein report a 72-year-old man with programmed cell death-ligand 1 (PD-L1)-negative lung adenocarcinoma harboring an EGFR mutation that responded to nivolumab for more than 2 years. A pathological examination revealed infiltration of CD8-positive lymphocytes and macrophages expressing CD68, CD206, and PD-L1 into the PD-L1-negative tumor; CD206 expression is a marker of immunosuppressive tumor-associated macrophages (TAMs). The presence of PD-L1-positive TAMs in the tumor environment might be a predictor of a positive response to anti-PD-1 antibodies.

Predictive Factors for Response to PD-1/PD-L1 Checkpoint Inhibition in the Field of Hepatocellular Carcinoma: Current Status and Challenges

Immunotherapies targeting immune checkpoints are fast-developing therapeutic approaches adopted for several tumor types that trigger unprecedented rates of durable clinical responses. Immune checkpoint programmed cell death protein 1 (PD-1), expressed primarily by T cells, and programmed cell death ligand 1 (PD-L1), expressed mainly by tumor cells, macrophages, and dendritic cells, are molecules that impede immune function, thereby allowing tumor cells to proliferate, grow and spread. PD-1/PD-L1 checkpoint inhibitors have emerged as a promising treatment strategy of hepatocellular carcinoma (HCC). However, only a minority of HCC patients benefit from this therapy. To find a niche for immune checkpoint inhibition in HCC patients, future strategies might require predictive factor-based patient selection, to identify patients who are likely to respond to the said therapy and combination strategies in order to enhance anti-tumor efficacy and clinical success. This review provides an overview of the most recent data pertaining to predictive factors for response to PD-1/PD-L1 checkpoint inhibition in the field of HCC.

Dendritic Cell Vaccination in Metastatic Melanoma Turns "Non-T Cell Inflamed" Into "T-Cell Inflamed" Tumors

Dendritic cell (DC)-based vaccination effectively induces anti-tumor immunity, although in the majority of cases this does not translate into a durable clinical response. However, DC vaccination is characterized by a robust safety profile, making this treatment a potential candidate for effective combination cancer immunotherapy. To explore this possibility, understanding changes occurring in the tumor microenvironment (TME) upon DC vaccination is required. In this line, quantitative and qualitative changes in tumor-infiltrating T lymphocytes (TILs) induced by vaccination with autologous tumor lysate/homogenate loaded DCs were investigated in a series of 16 patients with metastatic melanoma. Immunohistochemistry for CD4, CD8, Foxp3, Granzyme B (GZMB), PDL1, and HLA class I was performed in tumor biopsies collected before and after DC vaccination. The density of each marker was quantified by automated digital pathology analysis on whole slide images. Co-expression of markers defining functional phenotypes, i.e., Foxp3⁺ regulatory CD4⁺ T cells (Treg) and GZMB⁺ cytotoxic CD8⁺ T cells, was assessed with sequential immunohistochemistry. A significant increase of CD8⁺ TILs was found in post-vaccine biopsies of patients who were not previously treated with immune-modulating cytokines or Ipilimumab. Interestingly, along with a maintained tumoral HLA class I expression, after DC vaccination we observed a significant increase of PDL1⁺ tumor cells, which significantly correlated with intratumoral CD8⁺ T cell density. This observation might explain the lack of a significant concurrent cytotoxic reactivation of CD8⁺ T cell, as measured by the numbers of GZMB⁺ T cells. Altogether these findings indicate that DC vaccination exerts an important role in sustaining or de novo inducing a T cell inflamed TME. However, the strength of the intratumoral T cell activation detected in post-DC therapy lesions is lessened by an occurring phenomenon of adaptive immune resistance, yet the concomitant PDL1 up-regulation. Overall, this study sheds light on DC immunotherapy-induced TME changes, lending the rationale for the design of smarter immune-combination therapies.

Identification of a prognostic immune signature for cervical cancer to predict survival and response to immune checkpoint inhibitors

Cervical cancer (CC) is a leading cause of cancer-related death in women. Limited studies have investigated whether immune-related genes (IRGs) or tumor immune microenvironment (TIME) could be indicators for CC prognoses. The aim of this study was to develop an improved prognostic signature for CC based on IRGs or TIME to predict survival and response to immune checkpoint inhibitors (ICIs). A prognostic signature was constructed using bioinformatics method and its predictive capability was validated. The mechanisms underlying the signature's predictive capability were explored with CIBERSORT algorithm and mutation analysis. Immunophenoscore (IPS) is validated for ICIs response, and was therefore explored in relation to the signature. A prognostic signature based on 11 IRGs was developed. A multivariate analysis revealed that the 11-IRG signature was an independent prognostic factor for overall survival (OS) and progression-free interval in CC patients. In the 11-IRG signature high-risk group, CD8 T cells and resting mast cells, which are found to associate with better OS in our study, were lower; activated mast cells, associated with poorer OS, were higher, compared with the low-risk group. An IPS analysis suggested that the 11-IRG signature low-risk group, which possessed a higher IPS, represented a more immunogenic phenotype that was more inclined to respond to ICIs. In short, an 11-IRG prognostic signature for predicting CC patients' survival and response to ICIs was firmly established. The predictive capability of this model in CC requires further testing with the goal of better prognostic stratification and treatment management.

Monoclonal Antibodies in Dermatooncology-State of the Art and Future Perspectives

Monoclonal antibodies (mAbs) targeting specific proteins are currently the most popular form of immunotherapy used in the treatment of cancer and other non-malignant diseases. Since the first approval of anti-CD20 mAb rituximab in 1997 for the treatment of B-cell malignancies, the market is continuously booming and the clinically used mAbs have undergone a remarkable evolution. Novel molecular targets are constantly emerging and the development of genetic engineering have facilitated the introduction of modified mAbs with improved safety and increased capabilities to activate the effector mechanisms of the immune system. Next to their remarkable success in hematooncology, mAbs have also an already established role in the treatment of solid malignancies. The recent development of mAbs targeting the immune checkpoints has opened new avenues for the use of this form of immunotherapy, also in the immune-rich milieu of the skin. In this review we aim at presenting a comprehensive view of mAbs' application in the modern treatment of skin cancer. We present the characteristics and efficacy of mAbs currently used in dermatooncology and summarize the recent clinical trials in the field. We discuss the side effects and strategies for their managing.

Lymphovascular Invasion Is Associated With Mutational Burden and PD-L1 in Resected Lung Cancer

BACKGROUND

High tumor mutational burden (TMB) and programmed death ligand 1 (PD-L1) expression are leading biomarkers in metastatic non-small cell lung cancer (NSCLC) and predict favorable response to checkpoint inhibitors. We sought to identify clinicopathologic characteristics associated with elevated TMB and PD-L1 expression among patients who underwent resection for NSCLC.

METHODS

NSCLC patients undergoing primary resection (2016-2018) were prospectively enrolled in an immunogenomic profiling project. Multiplex immunofluorescence quantified densities (cells/mm²) of CD3⁺, CD3⁺CD8⁺, CD3⁺CD8⁺PD-1⁺, malignant cells (MCs), MCsPD-L1⁺, CD68⁺, CD68⁺PD-L1⁺, and CD20⁺ cells. Whole-exome sequencing quantified TMB (mutations/megabase). TMB and MCsPD-L1⁺ were dichotomized according to the median of each.

RESULTS

A total of 55 patients completed multiplex immunofluorescence and whole-exome sequencing profiling. In this sample, 41.8% (23 of 55) had pathologic stage I disease. Median TMB and MCsPD-L1⁺ were 3.91 and 0.62 cells/mm², respectively. TMB was higher among smokers (P = .001) and tumors with lymphovascular invasion (LVI) (P = .051). TMB was positively correlated with densities of MCsPD-L1⁺ (r = 0.293, P = .030), CD68⁺PD-L1⁺ (r = 0.289, P = .033), and CD20⁺ (r = 0.310, P = .043) cells. The density of MCsPD-L1⁺ was associated with increased CD3⁺CD8⁺ (r = 0.319, P = .018) and CD68⁺PD-L1⁺ (r = 0.371, P = .005) cells. Patients with PD-L1^HighTMB^High tumors (30.9%, 17 of 55) had higher intratumoral densities of CD3⁺, CD3⁺CD8⁺, CD68⁺, CD68⁺PD-L1⁺, and CD20⁺ cells. On multivariable analysis LVI was associated with synchronous elevated TMB and PD-L1 expression (odds ratio 3.53, P = .039).

CONCLUSIONS

NSCLC tumors with elevated TMB and PD-L1 expression are associated with LVI and increased intratumoral immune cell infiltration. These findings may potentially improve patient selection for checkpoint inhibitor therapy trials in the adjuvant setting.

The Role of the Lymphocyte Functional Crosstalk and Regulation in the Context of Checkpoint Inhibitor Treatment-Review

During the last decade, the dynamics of the cellular crosstalk have highlighted the significance of the host vs. tumor interaction. This resulted in the development of novel immunotherapeutic strategies in order to modulate/inhibit the mechanisms leading to escape of tumor cells from immune surveillance. Different monoclonal antibodies directed against immune checkpoints, e.g., the T lymphocyte antigen 4 and the programmed cell death protein 1/ programmed cell death ligand 1 have been successfully implemented for the treatment of cancer. Despite their broad activity in many solid and hematologic tumor types, only 20–40% of patients demonstrated a durable treatment response. This might be due to an impaired T cell tumor interaction mediated by immune escape mechanisms of tumor and immune cells as well as alterations in the composition of the tumor microenvironment, peripheral blood, and microbiome. These different factors dynamically regulate different steps of the cancer immune process thereby negatively interfering with the T cell –mediated anti-tumoral immune responses. Therefore, this review will summarize the current knowledge of the different players involved in inhibiting tumor immunogenicity and mounting resistance to checkpoint inhibitors with focus on the role of tumor T cell interaction. A better insight of this process might lead to the development of strategies to revert these inhibitory processes and represent the rational for the design of novel immunotherapies and combinations in order to improve their efficacy.

Predictive Biomarkers for Checkpoint Immunotherapy: Current Status and Challenges for Clinical Application

Immune-checkpoint blockade (ICB), in particular PD-1 inhibition, has rapidly changed the treatment landscape and altered therapeutic paradigms across many tumor types, with unprecedented rates of durable clinical responses in a number of cancers. Despite this success, only a subset of patients responds to ICB and, as a result, predictive biomarkers would be useful to guide the selection of patients for these therapies. This article highlights currently used biomarkers, as well as several promising novel candidates, and also discusses the challenges involved in establishing their analytic validity and clinical utility. Progress is being evaluated in melanoma and non-small cell lung cancer, for which PD-1 ± CTLA-4 inhibitors have become standard therapy, to other malignancies for which PD-L1 inhibitors remain investigational. Although single biomarkers have substantial limitations, a combination of biomarkers that reflect the interaction of host and tumor will likely be needed to provide a reproducible surrogate for the benefit of checkpoint modulation. Cancer Immunol Res; 6(10); 1122-8. ©2018 AACR.

The impact of CTLA-4 blockade and interferon-α on clonality of T-cell repertoire in the tumor microenvironment and peripheral blood of metastatic melanoma patients

Patients with metastatic melanoma were treated with tremelimumab and interferon-α (IFN) in a previously reported clinical trial [NCT00610857]. Responses were assessed by RECIST criteria as complete (CR) or partial (PR), stable disease (SD) or progressive disease (PD). In this study, T-cell receptor (TCR) beta-chain repertoire was immunosequenced in peripheral blood mononuclear cells (PBMC) specimens (N = 33) and tumor samples (N = 18) utilizing the immunoSEQ® Assay to determine repertoire clonality and T cell fractions at pre-treatment (tumor and PBMC), one month (PBMC) and 3 months (PBMC) time points and evaluate its association with clinical outcomes. In the pretreatment tumor microenvironment (TME), T cell clonality was significantly (p = .035) different and greater in patients who achieved disease control (CR, PR, SD) versus those with non-disease control (PD) as best response to treatment. Further, there was significantly (p = .001) increased TCR fraction in tissue of responders (CR, PR) versus non-responders (PD, SD). In examining T cell clonality in the circulation (PBMC), no significant associations were found in the pretreatment samples. However, early on-treatment (4 weeks) there was a significant decrease in T cell clonality that was associated with improved overall survival (p = .01) and progression-free survival (p = .04). In addition, analysis of temporal changes in tumor-infiltrating lymphocytes (TIL) and peripheral TCR repertoire revealed that responders had significantly higher clonal expansion of TIL in the circulation at 4 weeks than non-responders (p = .036). Our study provided interesting mechanistic data related to CTLA-4 Blockade and IFN and potential biomarkers of immunotherapeutic benefit.

A phase I study of the PD-L1 inhibitor, durvalumab, in combination with a PARP inhibitor, olaparib, and a VEGFR1-3 inhibitor, cediranib, in recurrent women's cancers with biomarker analyses

BACKGROUND

Strategies to improve activity of immune checkpoint inhibitors are needed. We hypothesized enhanced DNA damage by olaparib, a PARP inhibitor, and reduced VEGF signaling by cediranib, a VEGFR1-3 inhibitor, would complement anti-tumor activity of durvalumab, a PD-L1 inhibitor, and the 3-drug combination would be tolerable.

METHODS

This phase 1 study tested the 3-drug combination in a 3 + 3 dose escalation. Cediranib was taken intermittently (5 days on/2 days off) at 15 or 20 mg (dose levels 1 and 2, respectively) with durvalumab 1500 mg IV every 4 weeks, and olaparib tablets 300 mg twice daily. The primary end point was the recommended phase 2 dose (RP2D). Response rate, pharmacokinetic (PK), and correlative analyses were secondary endpoints.

RESULTS

Nine patients (7 ovarian/1 endometrial/1 triple negative breast cancers, median 3 prior therapies [2-6]) were treated. Grade 3/4 adverse events include hypertension (1/9), anemia (1/9) and lymphopenia (3/9). No patients experienced dose limiting toxicities. The RP2D is cediranib, 20 mg (5 days on/2 days off) with full doses of durvalumab and olaparib. Four patients had partial responses (44%) and 3 had stable disease lasting ≥6 months, yielding a 67% clinical benefit rate. No significant effects on olaparib or cediranib PK parameters from the presence of durvalumab, or the co-administration of cediranib or olaparib were identified. Tumoral PD-L1 expression correlated with clinical benefit but cytokines and peripheral immune subsets did not.

CONCLUSIONS

The RP2D is tolerable and has preliminary activity in recurrent women's cancers. A phase 2 expansion study is now enrolling for recurrent ovarian cancer patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02484404. Registered June 29, 2015.

Immunotherapy for hepatocellular carcinoma: recent advances and future perspectives

The introduction of immunotherapies has been a major development in the treatment of many advanced cancers, including hepatocellular carcinoma (HCC). We are entering a new era of systemic therapy for advanced HCC associated with an explosion of clinical trial activity. Data from phase I/II studies of checkpoint inhibitors in advanced HCC have been promising, with durable objective response rates of approximately 20% seen (in both first- and second-line settings) and acceptable safety profiles (including immune-mediated hepatitis). Phase III studies evaluating anti-programmed cell death protein 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) antibodies compared with sorafenib are already underway. The potential synergistic effects of anti-PD-1/anti-PD-L1 when used in combination with agents against other checkpoint molecules, systemic therapies, as well as conventional surgical and locoregional therapies are also being explored in upcoming clinical trials. Aside from this, other strategies to harness the immune system, including chimeric antigen receptor-engineered T cells, natural killer cell therapies, and peptide vaccines directed against HCC antigens have entered phase I/II studies. Current limitations of immunotherapies and areas of future research include the accurate assessment and prediction of tumor response, overcoming the immunosuppressive effects of a hypoxic microenvironment, and the management of immune-related hepatitis in patients who already have limited liver reserve.

A prospective observational study to assess PD-L1 expression in small biopsy samples for non-small-cell lung cancer

Background

Programmed cell death-1 (PD-1) immune checkpoint inhibitor antibody has proven to be effective in advanced non-small cell lung cancer (NSCLC) patients positive for programmed cell death-1 ligand-1 (PD-L1). However, there are currently no prospective studies evaluating PD-L1 expression for small biopsy samples.

Methods

To prospectively investigate the reliability of small samples for NSCLC, we included patients who underwent diagnostic biopsy by flexible bronchoscopy, computed tomography (CT) and ultra-sonography (US) guided core-needle to determine the PD-L1 expression status. In pathologically confirmed NSCLC, PD-L1 expression was evaluated using companion diagnostic PD-L1 immunohistochemistry. We evaluated: 1) tumor cell count and sample size, 2) tumor proportion score (TPS): <1, 1–49%, 50%≦, and 3) the concordance rate of TPS by biopsy and surgical samples.

Results

Of the 153 cases of PD-L1 expression, 110 were assessed using endobronchial ultrasonography guided transbronchial biopsy (EBUS-TBB) (thin bronchoscopy 84 cases; normal bronchoscopy 26 cases), 23 were endobronchial ultrasonography guided transbronchial needle aspiration (EBUS-TBNA), and 20 cases of CT or US-guided core-needle biopsy. Tumor cell count and sample size were significantly larger for normal bronchoscopy than thin bronchoscopy or EBUS-TBNA samples. Moreover, tumor cell counts for each subsequent biopsy decreased. In all cases, TPS distribution (undiagnosed, <1%, 1–49, 50%≦) was 2.6, 34.6, 31.4, 31.4%, respectively. TPS positive cases using thin bronchoscope was 55.9%, normal bronchoscope was 73.1% and EBUS-TBNA was 78.3%. In early stage adenocarcinoma, TPS was lower compared with advanced stages. Conversely, in squamous cell carcinoma, the rates of TPS were similar regardless of stage. The concordance rate of TPS by biopsy and surgical materials was 86.7%.

Conclusion

Utilizing smaller samples for evaluation, the frequency of TPS was comparable to past clinical trials using larger samples. The differences in TPS were influenced by diagnostic tools, cancer histologic types and staging. The concordance of TPS between EBUS-TBB samples and surgical materials was high.

Trial registration

This study was performed at the Department of Respiratory Medicine at St. Marianna University School of Medicine Hospital, with ethics approval (#3590) and registered as a clinical trial (UMIN000027030).

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5773-3) contains supplementary material, which is available to authorized users.

Combined BRAF and MEK inhibition with PD-1 blockade immunotherapy in BRAF-mutant melanoma

Oncogene-targeted therapy with B-Raf proto-oncogene (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors induces a high initial response rate in patients with BRAF^V600-mutated melanoma, with a median duration of response of approximately 1 year^1-3. Immunotherapy with antibodies to programmed death 1 (PD-1) produces lower response rates but with long response duration. Preclinical models suggest that combining BRAF and MEK inhibitors with PD-1 blockade therapy improves antitumor activity^4-6, which may provide additional treatment options for patients unlikely to have long-lasting responses to either mode of therapy alone. We enrolled 15 patients with BRAF^V600-mutated metastatic melanoma in a first-in-human clinical trial of dabrafenib, trametinib and pembrolizumab ( NCT02130466 ). Eleven patients (73%) experienced grade 3/4 treatment-related adverse events, the most common being elevation of liver function tests and pyrexia, most of which resolved with drug interruption or discontinuation of either the anti-PD-1 antibody or the targeted therapy combination. Eleven patients (73%; 95% confidence interval = 45-92%) had an objective response, and six (40%; 95% confidence interval = 16-68%) continued with a response at a median follow-up of 27 months (range = 10.3-38.4+ months) for all patients. This study suggests that this triple-combined therapy may benefit a subset of patients with BRAF^V600-mutated metastatic melanoma by increasing the frequency of long-lasting antitumor responses.

Radiologic features of pneumonitis associated with nivolumab in non-small-cell lung cancer and malignant melanoma

Aim: To assess the clinical features/imaging characteristics of pneumonitis reported during nationwide nivolumab postmarketing surveillance in Japan. Patients & methods: Clinical and radiological data were collected from pneumonitis cases reported during/after nivolumab treatment for melanoma or non-small-cell lung cancer. The expert central review committee evaluated each case. Results: Among 144 cases analyzed, 91 (63.2%) had radiological patterns considered typical for drug-induced pneumonitis and 53 (36.8%) patients had previously unobserved patterns with one or more atypical features, including 23 cases (16.0%) with ground glass opacity confined to the area around the tumor (peritumoral infiltration). A higher proportion of patients with (vs without) peritumoral infiltration had an antitumor response to nivolumab. Conclusion: Images of nivolumab-induced pneumonitis showed previously unobserved radiological patterns.

Oncolytic virus immunotherapy induces immunogenic cell death and overcomes STING deficiency in melanoma

Successful immunotherapy for melanoma depends on the recruitment of effector CD8⁺ T cells to the tumor microenvironment. Factors contributing to T cell regulation in melanoma have recently been recognized, including the stimulator of interferon genes (STING). Agents that can activate STING or enhance T cell infiltration into established tumors have become an important focus for further clinical development. Talimogene laherparepvec (T-VEC) is an oncolytic herpes simplex virus, type 1 (HSV-1) encoding granulocyte-macrophage colony stimulating factor (GM-CSF) and is approved for the treatment of melanoma and has shown therapeutic activity in murine tumors known to express high levels of STING. The mechanism of action for T-VEC has not been fully elucidated but is thought to include induction of immunogenic cell death (ICD) and activation of host anti-tumor immunity. Thus, we sought to investigate how T-VEC mediates anti-tumor activity in a melanoma model. To determine if T-VEC induced ICD we established the relative sensitivity of a panel of melanoma cell lines to T-VEC oncolysis. Following T-VEC infection in vitro, melanoma cell lines released of HMGB1, ATP, and translocated ecto-calreticulin. To identify potential mediators of this effect, we found that melanoma cell sensitivity to T-VEC was inversely related to STING expression. CRISPR/Cas9-STING knockout was also associated with increased T-VEC cell killing. In the D4M3A melanoma, which has low expression of STING and is resistant to PD-1 blockade therapy, T-VEC was able to induce therapeutic responses in both injected and non-injected tumors and demonstrated recruitment of viral- and tumor-antigen specific CD8⁺ T cells, and induction of a pro-inflammatory gene signature at both injected and non-injected tumors. These data suggest that T-VEC induces ICD in-vitro and promotes tumor immunity and can induce therapeutic responses in anti-PD-1-refractory, low STING expressing melanoma.

Extracellular Vesicle-Based Therapeutic Targeting of β-Catenin to Modulate Anticancer Immune Responses in Hepatocellular Cancer

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Although HCC can respond to immune checkpoint inhibitors, such as monoclonal antibodies against programmed death 1 (PD-1), many patients fail to respond or develop secondary resistance. Activation of Wnt/β-catenin signaling can contribute to immune evasion. Mutations in β-catenin are among the most frequent mutations associated with HCC. Thus, our aim was to directly target β-catenin to enhance the therapeutic response to immune checkpoint inhibition. A synthetic transgenic mouse model of experimental HCC induced by tyrosine-protein kinase Met/β-catenin expression and extracellular vesicles (EVs) as a therapeutic delivery agent was used to evaluate the efficacy of directly targeting β-catenin on the response to anti-PD-1. These studies showed that (1) oncogenic β-catenin could be therapeutically targeted using a biological nanoparticle-based delivery approach, (2) targeting β-catenin using small interfering RNA (siRNA) delivered within EVs can reduce tumor growth, and (3) the therapeutic response to anti-PD-1 can be enhanced by concomitantly targeting β-catenin using therapeutic EVs. These preclinical studies establish the efficacy of the use of biological nanoparticles as an endogenous delivery vehicle for therapeutic RNA delivery and support the use of therapeutic strategies targeting tumor-intrinsic β-catenin as an adjunct to anti-PD-1-based therapy. Conclusion: Combination therapy with anti-PD-1 and β-catenin siRNA delivered using biological nanoparticles provides an effective strategy for the treatment of HCC. This strategy could be further exploited into targeted approaches for immune potentiation by countering oncogene-mediated resistance to immunotherapies.

Efficacy and safety of programmed cell death-1/programmed cell death ligand-1 inhibitors in advanced urothelial malignancy: A systematic review and meta-analysis

INTRODUCTION

Programmed cell death-1/programmed cell death ligand-1 (PD-1/PDL-1) inhibitors are the newest class of approved drugs for advanced urothelial cancer (AdUC). This review aims to collate the evidence for their efficacy and safety in various treatment settings.

METHODS

Extensive search of databases was performed (updated May 2018) and the protocol was registered on PROSPERO (CRD42017081568). The review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. STATA (v 12) and Revman 5.3.5 were used for data analysis.

RESULTS

Ten nonrandomized, open-label clinical trials were included in this review. PD-1/PD-L1 inhibitors were used as second-line, stand-alone in eight trials and as first-line in cisplatin-ineligible in two trials. Heterogeneity was observed for study design, PDL-1 testing methods, cutoff criterias used and translational markers evaluated. The pooled objective response rate (ORR) was 18.2% (95% confidence interval [CI] 15.1-21.2, n = 1785) with PD-1/PDL-1 inhibitors in second-line settings as compared to 12.6% (95% CI 10.3-14.9, n = 736) with second-line chemotherapy and 23.7% (95% CI 19.9-27.4, n = 489) with PD-1/PDL-1 inhibitors as first-line therapy in cisplatin-ineligible patients. The median progression-free survival and overall survival was similar with PD-1/PD-L1 inhibitors in both second- and first-line treatment settings (1.5-2.9 vs. 2.0-2.7 months and 7.9-18.2 vs. 15.9 months) and second-line chemotherapy (3.3-4.0 months and 7.4-8 months). Odds of achieving ORR was 0.10 (95% CI 0.03-0.31, n = 229) in the second-line, stand-alone setting with a combined positive score (CPS) cutoff of 25% and was 0.34 (95% CI 0.19-0.62, n = 265) with a CPS cut-off of 10% in first-line setting in the cisplatin-ineligible.

CONCLUSIONS

PD-1/PDL-1 inhibitors appear to be promising in the treatment of AdUC and CPS may be a potentially reliable biomarker for predicting response but needs validation. Caution needs to be exercised until more data are available on imAEs and further studies are required to prove their worth as the standard of care.

Major pathologic response on biopsy (MPRbx) in patients with advanced melanoma treated with anti-PD-1: evidence for an early, on-therapy biomarker of response

BACKGROUND

With increasing anti-PD-1 therapy use in patients with melanoma and other tumor types, there is interest in developing early on-treatment biomarkers that correlate with long-term patient outcome. An understanding of the pathologic features of immune-mediated tumor regression is key in this endeavor.

MATERIALS AND METHODS

Histologic features of immune-related pathologic response (irPR) following anti-PD-1 therapy were identified on hematoxylin and eosin (H&E)-stained slides in a discovery cohort of pre- and on-treatment specimens from n = 16 patients with advanced melanoma. These features were used to generate an irPR score [from 0 = no irPR features to 3 = major pathologic response on biopsy (MPRbx, ≤10% residual viable tumor)]. This scoring system was then tested for an association with objective response by RECIST1.1 and overall survival in a prospectively collected validation cohort of pre- and on-treatment biopsies (n = 51 on-treatment at 4-week timepoint) from melanoma patients enrolled on the nivolumab monotherapy arm of CA209-038 (NCT01621490).

RESULTS

Specimens from responders in the discovery cohort had features of immune-activation (moderate-high TIL densities, plasma cells) and wound-healing/tissue repair (neovascularization, proliferative fibrosis) compared to nonresponders, (P ≤ 0.021, for each feature). In the validation cohort, increasing irPR score associated with objective response (P = 0.009) and MPRbx associated with increased overall survival (n = 51; HR 0.13; 95%CI, 0.054-0.31, P = 0.015). Neither tumoral necrosis nor pretreatment histologic features were associated with response. Eight of 16 (50%) of patients with stable disease showed irPR features, two of which were MPRbx, indicating a disconnect between pathologic and radiographic features at the 4-week on-therapy timepoint for some patients.

CONCLUSIONS

Features of immune-mediated tumor regression on routine H&E-stained biopsy slides from patients with advanced melanoma correlate with objective response to anti-PD-1 and overall survival. An on-therapy biopsy may be particularly clinically useful for informing treatment decisions in patients with radiographic stable disease. This approach is inexpensive, straightforward, and widely available.

Immunomagnetic isolation of circulating melanoma cells and detection of PD-L1 status

Personalised medicine targeted to specific biomarkers such as BRAF and c-Kit has radically improved the success of melanoma therapy. More recently, further advances have been made using therapies targeting the immune response. In particular, therapies targeting the PD-1/PD-L1 or CTLA-4 axes alone or in combination have shown more sustained responses in 30–60% of patients. However, these therapies are associated with considerable toxicities and useful biomarkers to predict responders and non-responders are slow to emerge. Here we developed a reliable melanoma circulating tumor cell (CTC) detection method with PD-L1 evaluation on CTCs. A set of melanoma cell surface markers was tested as candidates for targeted melanoma CTC isolation and a melanoma specific immunostaining-based CTC identification protocol combined with PD-L1 detection was established. In vitro testing of the effect of exposure to blood cells on melanoma cell PD-L1 expression was undertaken. Immunomagnetic targeting isolated melanoma CTCs in up to 87.5% of stage IV melanoma patient blood samples and 3 8.6% of these had some PD-L1 expressing CTCs. Our in vitro data demonstrate PD-L1 induction on melanoma cells in the blood.This study established a robust, reliable method to isolate melanoma CTCs and detect expression of PD-L1 on these cells.

Immunotherapy in extensive small cell lung cancer

Small cell lung cancer which constitutes about 15% of lung cancers is pathobiologically and clinically distinct from non small cell cancer. Histologically it is characterized by small cells with scant cytoplasm, absent or inconspicuous nucleoli, extensive necrosis, and expresses neuroendocrine markers. It is on a spectrum of neuroendocrine cancer that extend from typical carcinoids to large cell to small cell cancer. Clinically it behaves in a more malignant fashion with a rapid doubling time, early metastasis. They respond rapidly to cytotoxic treatment however tend to develop resistance soon. Immunotherapy with checkpoint inhibitors take advantage of PD 1 ligand-receptor axis between the tumor and T cells or CTLA4 on T cells which when engaged lead to inhibition of T cells. This inhibition helps tumors to evade immune surveillance. Checkpoint inhibitors break this axis by either binding to PD 1 ligands or PD 1 to CTLA4, thereby preventing tumors to evade the immune systems. This has led to remarkable responses in tumors. The immune related adverse effects can be severe however are experienced at much lower rates as compared to cytotoxic chemotherapy. Recently, CheckMate 032 has shown impressive response rates with Nivolumab and Nivolumab/Ipilimumab in relapsed small cell cancer. IMpower 133, a phase 3 trial showed that addition of Atezolizumab to Carbo/Etoposide led to a significant survival benefit in treatment naive extensive small cell cancer. This review will summarize recent developments and ongoing studies of immune therapy in extensive small cell cancer in addition to a brief summary of immune therapy landscape of Non small cell lung cancer. Investigational approaches to immune therapy have also been delineated.